var value = "yahoo.com";
value = "sina.com";
// 明确设置变量类型
var v = 100;
// v = true;
var state = true;
state = 1 > 2;
// 报错，number相加的返回值应该是number
// function sum(a: number, b: number):string {
//     return a + b;
//   }
console.log('123');
function sum(a, b) {
    return a + b;
}
function sum2(a, b) {
    return "结果是: " + (a + b);
}
console.log(sum(1, 2));
console.log(sum2(1, 2));
